Sensory perception during movement in man.

The ability of subjects to perceive innocuous stimuli in the presence and absence of movement was evaluated using electrical stimulation of the skin. The subjective intensity of suprathreshold stimuli was unchanged during movement. Discrimination of small differences in the intensity of suprathreshold stimuli (difference thresholds) was also not altered by movement while, in the same subjects, detection thresholds were increased during movement of the stimulated arm. These results suggest that the elevation of detection thresholds during movement can be explained by masking. Both active and passive movement of the stimulated limb increased detection thresholds, with active movement having a slightly greater and more consistent effect than passive movement. Thus, both central and peripheral feedback factors appear to play a role in diminishing one's ability to detect weak stimuli during movement. Attention was also shown to influence performance of the detection task.